1. Field of the Invention
The present invention relates to a movement used in an indication gauge provided in vehicles, aircraft, ships, etc.
2. Prior Art
There have been used a large number of conventional indication gauges having a movement device with a pair of cross coils generating magnet fields which are perpendicular to each other. The pair of coils each receiving a current varying with a measurement value generate the magnet fields. The combination of the magnet fields turns a magnet rotor fitted with a pointer. The pointer turns together with the magnet rotor to indicate the measured value.
FIG. 4 is an explanatory illustration showing a conventional indication gauge having a movement with a pair of cross coils. FIG. 5 is an enlarged explanatory illustration of the movement. FIG. 6A is s a general explanatory illustration showing mutually crossing inner and outer coils, and FIG. 6B is a general explanatory illustration showing an inner coil wound on a coil bobbin body.
Referring to FIGS. 4 to 6, an indicator movement having conventional cross coils and an indication gauge provided with such a movement device will be discussed hereinafter.
As shown in FIGS. 4 and 5, an indication gauge 100 has a movement 103 received in a shielding case 111. The case 111 accommodates a coil bobbin 104 wound with a pair of cross coils 105 consisting of an inner coil 105a and an outer coil 105b. The coil bobbin 104 has an upper cover 104a, a lower cover 104b, a flange 104c, a boss 104d, and a magnet rotor receiving chamber 104e. The rotor receiving chamber 104e is a space defined between the upper cover 104a and the lower cover 104b, in which there is turnably provided a disc magnet rotor 106 having a pointer spindle 107 engaged therewith. The upper cover 104a and the lower cover 104b are put together with securing screws 113. The joined upper and lower covers 104a, 104b, as shown in FIGS. 6A and 6B, constitute a coil bobbin 104 wound by a pair of inner and outer coil 105a, 105b which cross each other. In FIG. 6, denoted 104a is an upper cover.
The securing screws 113 serve also as terminals connected to the cross coils 105. Four securing screws 113 are spaced at a normal angle in perpendicular to the pointer spindle 107. Each securing screws 113 has an upper end coupled to a lead of the inner coil 105a or the outer the coil 105b. Meanwhile, in a lower end side of the securing screws, there is provided a printed circuit board 112. The printed circuit board 112 has a circuit pattern (not shown) for supplying electric current supplied from a control section. The printed circuit board 112 is secured to the securing screws 113, which electrically connects the circuit pattern to the securing screws 113.
In a central portion of the upper cover 104a, a generally circular boss 104d is provided outside the cross coils 105. The boss 104d has a small hole at the center thereof. The small hole turnably receives the pointer spindle 107 engaged with the magnet rotor 106.
The coil bobbin 104 has a pair of flanges 104c radially symmetrically extended at an upper side thereof. The flanges 104c compose abaseto fit an indication board 102 consisting of a dial board 114 and a light guiding plate 116. The indication board 102 is secured to the flanges 104c with securing screws 115. The indication board 102 has a through hole for the pointer spindle 107 extending therefrom.
The pointer 117 has a tapered main body 117a and a cap 117b joined to a pivot center of the main body 117a. At the pivot center, the cap 117b is engaged with an upper end portion of the pointer spindle 107 extending through the indication board 102. The dial board 114 has a printed scale for indicating a value of objective information. Denoted 108 is a hairspring for resiliently biasing the pointer 117.
The coil bobbin may be a movement consisting of a main case for receiving the magnet rotor and coil cores positioned so as to surround the rotor main case and wound with coiled wires. The coil cores are disposed in perpendicular to the rotormain case. In FIG. 7, there is shown such a conventional movement. In FIG. 8, another conventional movement is shown, and FIG. 9 shows a further other conventional movement.
For example, Japanese Utility Model Application Laid-open No. H. 3-110373 discloses an indicator movement having a movable magnet. As shown in FIG. 7, the movement has a housing 21 consisting of an upper cover 21a and a horizontally rectangular case 21b accommodating a magnet rotor. The case 21b has four side faces each fitted with a coil bobbin 26a wound by an electrical wire defining a coil 26 by bonding or the like.
Japanese Utility Model Application Laid-open No. H. 3-78268 discloses an indicator movement as shown in FIG. 8. The movement has a case 31 accommodating a circular plate shaped rotary magnet 38. Around the rotary magnet 38, there are disposed four generally circular coil bodies 36 or 37 circumferentially spaced from each other at a right angle in the case 31. The coil bodies 36, 37 each are wound with a copper wire 33 and each receive an outer rubber ring 34. The coil bodies 36, 37 are disposed in such a way that their central axes each are directed in a radial direction of the rotary magnet 38. The coil bodies 36, 37 each may have a leg for securing a bottom plate of the case 31 by soldering. The leg serves also as an electrical terminal of the coil bodies 36, 37.
Japanese Utility Model Registered No. 3002323 discloses an indicator movement as shown in FIG. 9. The movement has an upper seat 41 and a lower seat 42 for accommodating a rotary magnet therebetween. Around the magnet, there are disposed four bobbins 43 each wound with an electrical wire defining a coil 45. The bobbins 43 are secured to the upper and lower seats 41, 42 via tenons 411, 421 each extending from an outer side face of the upper and lower seats 41, 42. A pair of the tenons 411, 421 pass through an opening 44 formed in each bobbin 43. The tenons 411, 421 each have a fore end hook to lock it an edge of the bobbin opening 44.
However, the movement 103 having the conventional cross coils 105 shown in FIGS. 4 to 6 includes a disadvantage that it is a difficult work to evenly tightly wind electrical wires on the coil bobbin 104 to define the cross coils 105. That is because chuck tools for holding the coil bobbin 104 interfere with correct winding of electrical wires on the coil bobbin 104 to define coils. The movement 103 includes the pointer spindle 107 extending outward from the boss 104d disposed on the central portion of the upper cover 104a of the coil bobbin 104. The boss 104d with the pointer spindle 107 also interferes with winding of electrical wires on the coil bobbin 104, causing such damage as break or insulation stripping-off of the coiled wires. This may present an incorrect condition of the movement 103. Furthermore, the movement 103 has a complicated structure, which requires a skilled person for assembling thereof.
The movement shown in FIG. 7 includes the rectangular bobbin 21 having four side faces each fitted with the cylindrical coil bobbin 26a having the coil 26. The different conventional movement shown in FIG. 8 has the generally cylindrical coil assemblies 36, 37 disposed outside the rotary magnet 38 in the case 31. The further different conventional movement shown in FIG. 9 has the coupled upper and lower seats 41, 42 accommodating the magnet rotor, and on each of the four side faces of the coupled seat, there is fitted the bobbin 43 having the coil 45. These conventional movements shown in FIGS. 7 to 9 each have a main case accommodating a magnet rotor and coil bobbins with coils disposed outside the main case. Thus, each of the assembled movements includes vacant spaces, disadvantageously causing an enlarged dimension thereof.